Automatic telephone system.



A. B. Smm.

AUTQMATIC TELEPHONE SYSTEM.

APPLICATION FILED MAR` 25| 1914.

@wanted Mar. 12', .WM

42 SHEETS-SHEET I.

mvmm

A. B. SIVIIIH. AUTOMATIC TELEPHGNE SYSTEM.

APPLICATION FILED MAR. 25 1914.A

Patented MaLZ, 1918 mmw 2 SHEETS-SHEET 2.

. fir.,

MTHUR BESSEY SMITH, 0F EVANS'ION, ILLINOIS, ASSIGNOR TO AUTGMATIC COMPANY, 0F CHICAGO, ILLINOIS, A COBPORATIGN 0F ILLNOS.

annemarie TELEPHONE stsrnra.

Application filed March 25 To all 'whom t may concern Be it known that I, ARTHUR y BEssEY SMITH, a citizen of the Unitedy States of America, and resident of Evanston, in the county of Cook and State of Illinois, have invented certain new and usefullmprovements in Automatic Telephone Systems, of which the following is a specification.

My invention relates to improvements in automatic telephone systems and more particularly to improvements in the automatic switches employed in such systems.

Heretoi'ore, automatic selector and connector switches have been employed," which switches have one motion to select vgroup and a second motion to find a line in this selected group. In connection with the selector switches, this first movement has been a numerical movement-that is, a definitely controlled movement-while the second movement to select an idle trunk hasbeen non-numerical-that is, one which is automatically 'controlled by the switch itself, which movement is non-predetermined. In the connector switches both of these movements have been numerical operations.

n systems in which a ten point calling dial is employed-that is, a calling mechanism which is adapted injzsjen'd at the most ten impulses at any one: operation-the groups of contacts in the selector or connector switches have necessarily been limited to ten. By my invention, however, it is possible to -increase the numberof these groups and to have the selector or connectorswitch respond to two successive series of impulses to select a given group, and to then automatically select an idle trunk in the selected group, as in the case of a selector, orA to respond to the next series of impulses', -as in' the case of the connector, to 5nd a line in the selected group. Thus 1t is possible to 1ncrease the'capacity of an exchange without increasing the number of switches which it is necessary'to employ in establishing a connection between any two lines.

These and other objects of my inventionv will be more clearly understood by reference to they accompanying drawings, in which- `Figures l and 2 show a ,complete circuit connection in an automatic telephone system embodying the principles of my invention.

Fig. 3 is a detail view showing a portion of the switch shaft.

The automatic substation A (Fig. 1) com- Specification of Letters Patent.

Patented Mar, f1.2, 12rd,

serial no. scf/,cse

prises the usual receiver 2, transmitter 3, ringer-4 and condenser 5. lt is also provided with a. suitable -callsending` mechanism for controlling the automatic switches, which mechanism is represented diagram matically by a pair of impulse springs 25 and 26 and an impulse wheel 27, which lat-- ter may be controlled by aI dial- (not shown) provided with finger holes in such a way that the impulse springs may be momentarily separatedv a number of times corresponding to the respective digits of the number of the called subscriber.

The subscribers individual 'switch C (Fie. l) is of the general type of subscribers switch shown in British patent to R. V1. James No. 26,301 oi; 1906, being, however, of the particular type disclosed in British patent to T. G. Martin No. 1419 of 1910.

The master switch D (Fig. 1) is of the same general type as that disclosed inBritish patent t'oR. YV. James No. 26,301, referred to above, being, however, of the particular type disclosed in British patent to T. G. Martin No. 1419 of 1910, also referred to above. The function of the master switch,

in United States Letters Patent No.A 815,321, v I

granted March 13, 1906, to Keith, Erickson and Erickson, except that the co-called side switch is omitted, and the circuits are modified to adapt the switch to operate in a system in which the central ofiice apparatus is controlled by impulses delivered over the two sides of the line in series, as shown in Britishl patent to T. G. Martin No. 10,376 of 1912, and are further modiiied to operate in' accordance with the principles of my inven-f tion. Among other details, the selector E comprises a bank of contacts arrangede in4 horizontal rows or ievels, which con-tactsare adapted to be engaged by a set of wipers l ti line relay the group 'corresponding to the tenth step oil the' switch shaft being omitted for reasons to be hereinafter more clearly set forth. llnhe operation oi"v this switch shaft is controlled in the usual manner through the vertical magnet 1y and the rotary magnet 32. These magnets in: turn are controlled by the double-wound line relay 33, while the release of the switch is conm trolled by the release magnet 34, which, upon energizing, withdraws the retaining pawls trom the shaft. This selectoris liliewiseprovided with a pair of slow acting relays 37 and 38that is, relays which are slow to release their armatures upon denergisting-a locking relay 86 and a switching relay 87, the controlling circuits and operations of which magnets will be more clearly set forth when the operation of the switch is described. Located in the circuit of the rotary magnet there is a pair of normally closed contact springs 39, which are adapted to be separated when the switch shaft is raised to the tenth step, in the manner shown in '8. :l

The connector switch l-l (Fig. 3) is of the saine general type of connector switch disclosed in United States Letters Patent No. 815,176, granted March 13, 1906, to Keith, Erickson and Erickson, the circuits, however, being modiiied to adapt the switch to operate in a system in which the central oiice apparatus is controlled by impulses livered over the two sides of the line in series, as shown in British patent to T. G. Martin No. 1419 of 1910', hereinabove referred to. Among other details, the connector' H comprises a bank oi? contacts arranged in horizontal rows or levels, which contacts are adapted to be 4engaged by a set of wipers 43, 44 and 45 carried upon a shaft (not shown) which has a vertical movement controlled by the vertical magnet 46 and a rotary movement controlled by the rotary magnet 47. The shaft of the connector switch is likewise provided with twenty vertical teeth., whereby this shaft can be raised through twenty steps, in a manner similar 'to the selector shait shown in Fig. 3. The operations of the switch are controlled through the medium of the double-'wound 41, which is bridged across the trunk.. The connector", is likewise provided with the usual baclcb 'i'dge relay 41), through the windings of which the called line is provided with talking, cilrrent, together with the slow acting rela," 56 and 57 and the release magnet 53, th busy relay 153 and the private magnet 42'.' This private magnet controls the usual side switch comprising the wipers 48, 49, 50i, nd 51. The circuits and operations of theseJ relays and magnets will ,be more clearly inted out in the de'- scription ,of the oper tion of this switch. pair of normally opel contacts 139 is likeole-l ,"trunk,

nascose wise provided, which contacts are adapted to be closed when the switch sha'f't is raised to the tenth level. rhe springs 54 and 55 are normally open and are adapted to bc closed when the switch has been raised one or more steps from its lowest position. Ringing current is adapted to be supplied to the called line from the generator lt, the application of this ringing current being controlled by the ringing relay 52 and the ringingjcut-o relay 102. 'Busy signaling current is furnished in the usual well-known mannerierom the busy signaling machine Q.

The line switch C' and the subscribers substation A are similar to the line switchy C and the subscriberls/substation A.

f1 general description of the `Mnparatus having been given, it will now be explained how a connection can. be established between the line ci' substation A and the line of a called substation A.

Since the apparatus disclosed herein is in general well known i/n the art, and is described in the publications herein referred to, its operation will be explained in a more or less general way.

When the subscriber at substation A removes his receiver 2 preliminary to making a call, an energizing circuit is closed through the -linewinding of the line switch C, whereupon this line switch operates in the well-known mannento connect Iwith a idle which we will assume to be the one extending to the selector E. This operation is fully described in the patents referred to, 100 and as it forms no part of my present in vention it is not thought necessary to further describe the same. When the connection is thus extended to the selector E, the line relay 33 is energized over a "circuit eX- 105 tending from ground G3 through the lower winding of the relay 33, springs 70 and 71, springs and 16, conductor 66, substation A., conductor 57, springs 13 and 17, springs Y 72 and 78 and the upper winding of the 110 relay 33 to battery B. The relay 33, upon energizing, closes a circuit fr m ground. G4 through the springs 74 and 5 and the relay 37 to battery B. The relay 37, upon energizing, closes a circuit from ground G5 115 through the springs 76 and springs 18 and 14 to the point 77 thence one `branch eX tends over conductor 78 to the nnector private bank contact associated-iaith the calling line and multiples of thetsame, This 120 guarding potential prevents afny subscriber from connecting with the substation A when said substation is calling. nother branch extends from the point 77 through the holding winding 9 ofthe line switch C to bat- 125 tery B. This circuit through the holding winding 9 is closed beiiorethe armature t0 Jfalls back after the circuitcthrough the line winding 10 is broken by the attraction of the armature 12. The armature does not 130 A UY assenso ran pack immediately upon thepulliingI up of theyarmature4 l2, due to the fact'jhat simultaneous with the attraction of the' armature l2 is the pullingup of the vplunger' arm 6, which short-circuits the auxiliary winding ll by closing the springs 7 9. This short-circuiting of the winding ll tends to retardlthc denergizatton 'of the core and thus the armaturejfisheld in an operated position. until enough time has` elapsed for the circuit through the winding 9 to be closed, whereby the plunger arm 6 is held in an operated position.

rlhe calling subscriber now operates his calling device for the first digit of the called number. Assuming that this digit is any number from l to 9, such as two, the operation of the calling device causes the substation impulse springs 25 and 26 to b e separated twice momentarily, each time breaking 'the circuit of the line relay 88 of the selector E. The relay 87 of the selector being slow acting does not denergize during the momentary interruptions of its circuit by the relay 88,' and consequently each time the latter relay denergizes, an impulse is transmit.-v ted over the circuit extending from ground G4 through the springs 74 and 80, springs 8l, springs 82Jand 88, relay 88 and the vertical magnet 3l to battery B. The vertical magnet receives two impulses over this circuit and operates to raise the switch shaft and wipers two'steps to a position opposite the second row or level of bank contacts, and at the same time the shaft-controlled contacts 85 and 86 are closed. Theslow acting relay 38 is maintained in its energized position continuously while impulses are being transmitted to the vertical magnet through it, and in its energized position closes a circuit extending from ground GG through the springs 84 and 85 and the relay 86 to battery B. rEhe relay 86, upon energizing, forms a locking circuit for itself extending from ground G5 through the springs 76, springs 2l, off-normal springs 86, springs and 2-1 and the relay 86 to battery B. Thus upon the denergization of the relay'88 after the last impulse is delivered. to the vertical msgnet, the relay 86 remains energized and thecircuit. of the rotary magnet 32 is closed, which circuit extends from ground through the springs, springs 21, offnormal springs 86 springs 23 and 2,4, springs 85 and 58, springsl9,'springs 22 and the rotary magnet 32 to-bat'teryr-B, The rotary magnet 22, upon energizing, rotates'the shaft wipers one step and, by opening'thesprings 2l and 22, disconnects ground-G5 from itself and from the relay 86. lf the first trunk line of the second level is idle, the relay 86 deenergizesf as soon as the springs 21 are opened. if this trunk line is busy, however, the privateV wiper 29 nd the Contact which it engages provided with a guarding ground 86 through the springs 23 and 24, thereby preventing it from denergizing. The ro tary magnet 82, however, de'energizes when the springs 22 are opened, regardless of whether the relay 86 remains energized or not. f the relay 86 remains energized, the circuit of the rotaryv magnet will be again closed as soon as its armature 'drops back far enough to close the springs 2l and 22. The rotary. magnet will, therefore, operate in a manner similar to that of a buzzer to advance the wipers step by step over the contacts until the non-grounded contact of an idle trunk line is reached by the wiper 29, whereupon the relay 86 denergizes. The relay 86, upon denergizing, whether after one or several operations of the rotary magnet, permanently breaks the circuit of said rotary magnet and closes the circuit of the switching relay 87, which circuit extends from ground G5 through .the springs 76, springs 2l, olf-normal springs 36, springs 28 and 88 and the relay 87 to battery B. The

relay 87, upon energizing, ydisconnects the line relay 33 from the line and4 extends the line connection over the heavy conductors shown through the wipers 28 and 30 to the connector H. I

If, however, in extending la connection it was .necessary that the selector switchv be raised to a level above the -tentlr level, the twelfth level for instance, in order to extend the connection to the called line, the calling subscriber would first operate the calling device for the digit 0, which loperation sends ten impulses over the line, and which ten impulses would operate to 'raise the selector E to the tenth level in a manner similar to that just described, and, as has Abeen previously stated, in this position of the shaft the normally closed contact. springs 39 in the circuit of the rotary magnet are opened. As a result, when the relay 38 denergizes after .the last vertical impulse has been delivered to the vertical magnet through it,-the circuit of the rotary magnet will not be closed, due to the opening of the springs 39. Consequently, when the4 calling subscriber oper-f ates his calling device for the second digit 2,

the vertical magnet of the selector E again operates to raise the switch shaft and wipers two steps to a position opposite the twelfth row or level of bank contactsi Since the springs 39 are opened only while the switch shaft is standing'at the tenth vertical step, the denergization of the relay- 38. will now close the circuit of the rotary magnet 32, which will operate in a manner hereinbefore explained to advance the shaft wipers over the bank contacts until an fidle trunk line leading to an idle connectoreswitch is found. p

T he line relay ll of the connector H thereupon becomes energized and closes the circuit of the relay. 56, which in turn, upon .vate wiper Lillie energizing, completes a circuit extending irough the springs 89, private wiper 29, springs 23 and 88 and the relay, S7 to battery B. A branch of the above circuit may be traced from the priy through the volii-normal springs 36, springs ,211 to the holding winch ing oit the line switch C over the circuit previously traced. ylliis circuit maintains the relay 87 and the winding 9 energized after their origina-l energizing circuits are broken by the relay 3'?, which denergizes shortly after the line relay 33 is disconnected from the line.

rlhe calling subscriber now operates the calling device for the next digit of the called number, which we will assume "to be 2, whereupon the substation impulse springs and 26 are separated. twice momentarily, each time breaking the circuit ot the line relay l-l. oi the "connector H. of the connector being slow acting does not denergize during the momentary interruptions of its circuit by the relay lll, and consequently each time the latter relay (lechergizes, an impulse is transmitted over the circuit extending from ground G8 through the springs 90 and 9i, springs 92 and 93, relay 57, vertical magnet 46 and the side switch wiper i8 (in first position) to battery B. Theivertical magnet receives two imfrom ground G7 pulses over this circuit and operates to raise the switchshaict andwipers two steps to a position opposite the secondrow or level of bank contacts and at the same time the shaft-controlled contacts 5d and 55 are closed. The slow acting relay 57 is maintained in its energized position continuously while impulses are being transmitted to the vertical magnet through it, and in its energi'zed position clses a circuit from ground Gr through the springs 94e and 95 and the private magnet i210 battery B. This circuit is broken when the relay 57 de nergizes after the last impulse has been delivered to the vertical magnet.' The breaking of this circuit causes the private magnet i2 to de energize, thus permitting the side switch to pass to second position. In passing from first to second position the side switch wiper 48 transfers the battery connection I'from the vertical magnet i6 to the rotary magnet Ll?.

lf, however, terminated in a level ot the connector above the tenth level, such as the twelfth level, it would then be necessary for the calling suhn scriber to lirstoperate his calling dial for the digit @to thus raise the switch shaft ot the connector to the tenth level and to then operate hisdial -ior the digit 2, which would raise the switch shai't two more steps to the twelfth level. This operation is rendered possible to: the reason that when the switch shaft of the connector reaches the Atenth level, the contact springs 139 are tained in irst position and The relay 55.

llav 5? operates inresponse the called suhscrib'ers line` closed, which clotes a. ground connection through the private magnet 42, 'thus preventing this private magnet from dener gisting aiter the first series ot impulses is receivedand thus the side switch is main.- n

the nent series oi' impulses pass 'through the vertical inagnet to raise the switch shaft the two additional steps necessary is soon as the switch shaft 'is raised above the tenth level, the springs 139 again. separate and thus, alter these two impulses have heen transmitted, the private magnet denergises in the usual manner and the side switch is tripped to second position and the battery connection transferred from the vertical magnet i6 'to the rotary magnet t?.

The calling subscriber new operates vhis calling device for the last digit, which l will assume to be 2, in response to which the connector line relay operates to transmit two',l impulses through the .rotary magnet ll whereby the shaft wipers are rotated onto the contacts of the desired line, cuit or" the rotary entends trom ground Gg thi gli the springs 90 and 9i, springs 92 and 93, relay 5'?, springs 95, rotary magnet 4:7 and the sideswitch wiper ed (in second position) to battery B. iThe reto the impulses for this digit in the same manner as tor the previous digit to cause the private magnet 4t2 to advance the side switch to third positione By the engagement of the side switch wipers e9 and 50 with their third-position contact points, the line connection is coinpleted with the called line. Upon the en- The ein y nector private henk contact associated with.

the called line prevents the called line troni.

being seized hy sonic other connector switch. By the engagement or the side switch wiper @L8 with its third-position Contact pointfthe circuit of the ringing relay 52 is closed. This circuit extends from ground ,G11 through the interrupter. 9i), ringer relay 52,

springs 100 and the side switch wiper e8.

(in third position) to battery B, The ringer relay is energized intermittently, interruptor 99, and operates to disconnect the calling line from the called line and t6 bridge the ringing current generator R across theY called'line to signal the called subscriber. Upon the removal ot the redue to the separate and distinc ill to impulses to vother series for con `invention in connection intenta-- ceiver the cuit from ground G10 ,through the side switch wiper 5l (in third position), springs lOl, relay 102 to battery B. The relay 102, upon energizing, opens the circuit of the ringer relay 52 at 'the springs 100 and closes a locking circuit for itself through the springs; 103 independent of the springs lOl.

Upon the completion of the conversation, the ea ling-subscriber, hy returning his receiver to the switch hook, opens the circuit or" the connector line relay al. The relayll, upon denergizing, opens the circuit of the relay 56, which in turn, upon denergizing, removes the holding ground for therelay 8'? and the winding 9, and in addition closes a circuit from ground GB through vthe springs 90 and '9.1, springs 92 and 104, vodnormal springs 54 and the release ymagnet 53 to battery B. The release magnet, upon energizing, operates to remove the retaining pawls from the shaft and its own circuit is opened 'nt the springs ol 'when said shaft reaches its lowest position. The denergization of the relay 87 of the selectr E ccmpletes a circuit from ground G4' through. the springs el and 80, springsl, springs 82. and 105, olii-normal springs and the release magnet to battery l The' release magnet, upon energizing, op rates to remove the retainine pawls from the shaft and its own circuit is opened the springs 35 'when said shaft reaches its lowest position. rlhe deenergiz tion of the winding 9 of the line switch C releases the plunger armati and the cut-ofi armature l2, thus allowing` the -line switch C to return to normal.

lt will thus he seen that l have devised very efficient automatic switches, which switches have three distinct,movenients,'two of which movements are controlled loy one motor magnet, while the third movement is i controlled by a 'seperate motor magnet.

s, hy nfiy invention l provide a switch havinglout two mot r magnets, and the first oit these motor ma@ .ts is responsive to two L da,

operate the switch to lect a group, while the second motor mag. Jt is then responsive ine in the` selected am enf-hied to ingroup. ln this manner crease the capacity of 'ssvitc i* ithout inl or' sing` the number or .ir in any trolling the operation or" .this switch.

l'fhiie l have illustrated and described my with automatic switches of well known types, "which switches have first a vertical motion for selooting groups and then a rotary motion for finding a line in the selected group, it will, of course, be understood that my invention called substation, a circuit will .he closed through the naclebriolge relay d0. Said relay, upon energizing, 'will close a cireries of impulses to e switch. having forms of automatic switches in which dit y ferent characters of movement are employed for selecting groups and lines.

What l claim as my invention is 1. ln a telephone system, an automatic switch, a plurality oi groups of lines termi nating in said switch, a motor magnet, means for transmitting of impulses to said switch to operate said motor-@magnet to cause said switch to select a group, a second motor magnet, and means for then operating said second motor magnet to connect with a line in the selected group.

2. In a telephone system, an automatic switch, and a plurality of groups of trunk lines terminating in said switch, said switch having a plurality of numerical operations to select a group, followed by a numerical operation for inding a line in the-selected switch, and a plurality of lines divided into.

groups terminating therein, said switch .raving three successive' numerical operations for rst and for then finding group.

5. ln a telephone system, an automatic a line in the selected Aswitch having vertical and rotary motion,

trunk -lines divided into a plurality. of

groups terminating therein, a vertical magfnet for controlling the vertical vmovement of said switch, a rotary magnet for controlling rthe rotary movement of said switch, lmeans for transmitting plurality of series of impulses through said vertical magnet to raise saidswitch to proper level, and means for then operating said rotary magnet to rotate said switch to connect with the desired line.

6. ln a telephone system, an Iautomatic switch havinga pair of operating magnets, means for `transmitting a series of impulses to said switch, means for causing said impulses to cause the operation of said, irst magnet, said first means also for transmitting a secondseries of impulses to said of said second magnet.

7. ln a telephone system, an automatic fi .eilt ef @refe-rims .essentie a plurality of series and at another time to selecting a .group of lines switch, means for causing said second series magnet when a cerswitch having vertical and rotary motion,

trunk lines divided into a plurality of pulses through said vertical magnet to raise said switch to a proper level, means for then operating said rotary magnet'to rotate said switch to connect with the desired line, andv means for controlling the operation of said Iswitch over two sides of a line circuit in series.

20. In a telephone system, an automatic switch having a pair of operating magnets, l means for transmitting a plurality offseries of impulses over two sides of a line circuit in series to said switch, means for causing the rst series of impulses to cause the operation of said rst magnet, means for causing the second series of impulses to cause the operation of said second magnet,'and means controlled by the operation of said first magnet when a certain number of impulses are transmitted to said switch for reventing saidy second series of impulses rom causing the operation of said second magnet.

21. In 'a telephone system, an automatic switch having a pair of operating magnets, means for transmitting a plurality ot' series of impulses over two sides oi a line circuit in series to said switch, means for causing the iirst series of impulses to cause the operation ot said iirst magnet, means for caus ing the second series of impulses to cause the operation of said second magnet, and means controlled by the operation of said first magnet when a certain number of impulses are transmitted to said switch for preventing said second series of impulses from causing the operation of said second magnet and for causing said second series of impulses to then cause a further operation of said irst magnet.

22. In a telephone system, an automatic switch having vertical and rotary movement, a vertical and a rotary magnet for controlling the operation of the same, normally closed contacts in the circuit of said rotary magnet adapted to be opened when said vertical magnet has been operated'fa predetermined number of times, and means for controlling the operation of said switch over two sides of a line circuit in series.

23. In a telephone system, an automatic switch having a plurality of operating magnets, a switch for shifting the connection -from one to the other of said magnets, means for transmitting a plurality of series of impulses over two sides of a line circuit in series to said switch to cause the operation of said magnets and for shifting the con-A nection from one to the other of saidV ,mag-

nets, and means for preventing said connection being shifted when a predetermined number of impulses are transmitted to said switch.

24. In a telephone system, an automatic switch havinga pair of operating magnets, aside switch adapted to shift an operating connection from one tov the other of said magnets, means for transmitting a series ot impulses through the first of said magnets, means for then operating said sideI switch to switch the connection to the second of said magnets, means for preventing the operation of said side switch when said iirst magnet has been operated a predetermined `vnumber of times, and means for controlling the operation ofv said automatic switch over twosides of a line circuit in series.

25. In a telephone system, an automatic switchv having vertical and rotary motion, a vertical and a rotary magnet for contro-lling the operation of the same, a side switch,

means for first operatingsad .vertical magnet to raise said switch a jde'sired number of steps, means for then operating said side switch to render said vertical magnet inoperative and render said rotary magnet operative, means for preventing said operation of said side switch when said vertical magnet has operated. said switch a predeter mined numberotl steps, and means tor controlling the operation of said automatic 'switch' over two sides of a line circuit in series. i.

26. In a telephone system, an automatic switch having vertical and rotary magnet, a vertical and a rotary magnet for control ling the operation of same, a private magnet, a side switch controlled thereby, means for transmitting a plurality of impulses through said vertical magnet to operate said automatic iv vitch, means for then operating said private "magnet to-cause theoperation of said .side switch, means controlled by a predetermined operation of said vertical magnet for `preventing this operation of the private magnet, and means for controlling the operation of said automatic switch over two sides of a line circuit in series.

27. In a telephone system, an `automatic switch having a progressively movable element, a pair of. operating magnets for co'ntrolling said element, 'circuits for said inagshaft, la vertical operating magnet and a rotaryv operating magnet, for controlling said shaft, a circuit for said rotary magnet, said circuit controlled at one point when said switch is in normal position and again off normal position.

29. ln a telephone system, a progressively movable element, a pair of coils, means* conn trolled by said coils tor moving saidjele ment, a circuit including 'fone of said coils said circuit controlled by said means, and second, means for energizing `the othero said coils whereby said first Ameans may lo' controlled to in turn control the said circuit of the tir-st one of said coils.

30. ln a telephone system, a progressively movable element, a pair of coils, means controlled by said coils for moving said element, a circuit including one of said coils, said circuit controlled by said means, and a sec-v ond means for energizing the other of said coils whereby said iirst means may be controlledto close the said circuit and also to open said circuit. y

31. ln a telephone system, a progressively movable element, a 'pair of coils, means controlled by said coils for movingfsaid element, a circuit including one oi said coils, 'p said circuit controlled by said means, and a second means 'for energizing the other of said @coils whereby said irst means may be conrtrolled to first close the circuit of the first .f coil .at one point and to thereafter open the said circuit at another point.

ln a telephone system, an automatic switch'having a switch shaft and a pair ot' magnets for operating said shaft, a plurality of pairs of contacts included in the circuit 'of one of' said magnets, said shaft controlled f by the other of said magnets t directly control said pairs ci? contacts.

` 33. lua telephone system, an automatic switch havingra switch shaft and a pair of `inauguste torfoperating saidshait, a plurality or. pairs ot contacts included 'in the circuit ci" one oi said inagnetasaid shaft controlled .fbi/ lalle luther ont said magnets, to directly control `pairs oiV contacts and rneans for controlling the operation of said switch over the two sides of a line in series,

'34. ln afslephone exchangesystem, in-

- coming linesfand groupsot' outgoing lines, asselector switch for extending an incoming' line to an outgoingaline, means tor control-- ling said switch to select one group of out 'ggoing lines, automatic means operative thereupon for causing said switch to select an idle one of the selected group olines, and means for delaying the operation of said automatic means it another group ot .outgoing lines has been selected;

` 35. ln a telephone exchange system, in-

coming lines and groups of outgoing lines, a selector switch tor ent/ending an incoming line to an outgoing line, means :for producing series oi impulses in said incoming lii 3,

primary and .a secondary electromagnet tor controlling the operation ci said switch,

f ineens :lion operating said pry electrics assenso magnet in accordance with one series of impulses, automatic nieans operative thereupon for actuating said secondary electromagnet, and means for delaying the operation of said automatic means if said primary magnet has been controlled in accordance ywith another series of impulses,

36. ina selector switch, a directive-ly operable primary magnet and an automatically o erable secondary magnet for controlling t 1e operation ot said switch, means tor actuatingsaid secondary magnet after a com pleted operation of said primary magnet, and means for operating said primary magnet by a plurality oft series oi' impulses prior to the actuation of said secondary magnet.

37. ln a telephone exchange system, incoming lines and groups of outgoing lines, a. selector switch for extending an incoming line to an outgoing line, means controllable over said incominglines for .causing said switch to select an outgoing line in acertain group, and means for causing said switch to select an out-going line in a predetermined group if it is controlled to select a line in a certain otherI group.

38. ln a telephone exchange system, incoming lines and groups of outgoing lines,

a selector switch for extending an incoming line to an outgoing line, means for controlling said switch to selectone group ot said i outgoing lines, means operative thereupon for controlling said switch to select an idle outgoing line in the selecieilfgroup, and means for causing said switkdi to select an idle outgoing line in afpredeterniined group it the switch is controlled to select another group of said outgoing lines.

39. ln a telephone exchange system, inl ooming lines and groups of outgoing lines, a selector switch'for extending an incoming line `to an outgoing line, means controllable over said incoming lines for causing said switch to select a group of said outgoing lines, automatic means jlor Iv'causing said switch to select an idle line ink the selected group, and means for causing the selection of an idle outgoing line in another group than the selected one. I

eldln telephone exchange system, incoming lines and4 groups of outgoing lines, a selector switch for fnrtending al calling incoming line to an outgoing line, an electromagnet controllable over said incoming lines for operating said. switch to select a group ot outgoing lines, another electromagnet for causing said switch to select an idle outgoing line, and means for causing said switch to select anl idle outgoing line in another group than the selected one.. y vn a telephone system, an automatic an operating magnet therefor, two main groups ci trunk lines terminating cwi 'ch,`eachniain group being divide'V a single series of iml'nilscsl to operate said magnet to cause said mitch to select a subgroup in one of said main groups, said means also for transmitting two series oi impulses to said magnet to cause said switch to select a sub-group in the other of said main groups.

42, in a telephone system, an yautomatic switch, an operating magnet therefor, two main groups of trunk lines terminating in said switch, each main group being divided into subgroups, means for transmitting a single series of impulses to operate said magnet to cause said switch to select a sub-group in one of said main groups, said means also for transmitting two series of impulses to said magnet to cause said switch to select a sub-group in the other of said main groups, a second operating magnet for said switch, and means for operating said second magnet to select an idle trunk line in the selected sub-group of either main group.

43. In a telephone system, a combined iirst and second selector switch, a. directively operable primary magnet for controlling the operation of said switch, and means in one instance for operating said primary magnet by the impulses corresponding to the first digit only of the called number, said means in another instance for operating said primar f magnet by the impulses corresponding to the tirst and second digits of the, called number.

44. In a telephone system, a combined first and second selector switch, a directive'ly operable primary magnet and an automaticall operable secondary magnet for control ing the operation of said switch, means in one instance for operating said primary magnet by the impulses corresponding to the first digit only of the called number, said means in another instance for operating said primary magnet by the impulses corresponding to the first and second digits of the called number, and means for actuating said secondary magnet after completion of either operation of said primary magnet.

Signed by me at Chicago, Cook county, Illinois, this 12th day of March, 1914.

ARTHUR BESSEY SMITH. Witnesses:

GEORGE YANooHoWsKI, HERBERT W. Kaaoim. 

